1. Field of the Invention
The present invention relates to a cutting device used to cut sheet-shaped objects, such as documents or elongated thermal paper used for recording transmitted massages in a facsimile machine.
2. Description of the Related Art
FIG. 1 shows an example of a conventional cutting device. The conventional cutting device shown in FIG. 1 includes: a frame 101E; a fixed blade 102E having a linear cutting edge 122 and fixedly attached to the frame 101E; a pair of side shafts 130C, 130D; and a movable blade 103E having a linear cutting edge 132. The movable blade 103E is supported at end portions 103c, 103d thereof by the support shafts 130c, 130d respectively so that the movable blade 103E is disposed slightly in intersection with the fixed blade 102E. The fixed blade 102E is formed from a uniformly thick metal plate, for example, bent into a substantially L shape in cross section so that the lower edge of the fixed blade 102E is integrally linked with the support member 121E. The support member 121E uniformly supports all positions in the lengthwise direction of the lower edge of the fixed blade 102E.
The movable blade 103E is rotatable in a vertical direction indicated by an arrow N1 and is freely movable toward and away from the fixed blade 102E accordingly. Also, rotational center line of the movable blade 103E is slanted in a vertical direction with respect to the fixed blade 102E by an appropriate angle .theta.. It should be noted that the appropriate angle .theta. is shown exaggeratedly large in FIG. 1 in order to facilitate its understanding.
With this configuration, when the movable blade 103E is rotated downward so as to move closer to the fixed blade 102E, the cutting edge 132 of the movable blade 103E presses against the fixed blade 102E in the blade thickness direction, indicated by an arrow N2, at portions following the lengthwise direction of the fixed blade 102E from the end 102c to the other end 102d. In this type of cutting device, cutting operation of the cutting edges 122 and 132 cuts across the width of elongated sheets supplied between the fixed blade 102E and the movable blade 103E.
In order to appropriately cut the sheet using this type of cutting device, it is necessary that the fixed blade 102E and the movable blade 103E uniformly contact each other along the lengthwise edges of the cutting edges 122, 132. In order to ensure that the fixed blade 102E and the movable blade 103E contact each other uniformly at all positions in the lengthwise direction, it is necessary to position the fixed blade 102E and the movable blade 103E with extreme accuracy so that they slightly intersect each other and their the cutting edges 122, 132 appropriately contact each other.